The Path to Maturity

Science's STKE  24 Aug 2004:
Vol. 2004, Issue 247, pp. tw305
DOI: 10.1126/stke.2472004tw305

To efficiently activate T cell immunity, dendritic cells (DCs) must undergo a program of maturation steps to allow them to become proficient at taking up antigen and activating T cells. West et al. observe that DC maturation includes a previously unappreciated early acute response after activation via Toll-like receptors. A transient phase of endocytosis that involved redeployment of the actin cytoskeleton ultimately led to increased antigen presentation. Benvenuti et al. show that at a later stage of maturation, DCs use the guanosine triphosphatases Rac1 and Rac2 to extend the cytoskeleton to form critical membrane contacts with activating T cells. The two studies reveal a dynamic and highly regulated orchestration of actin cytoskeleton deployment at distinct stages of the DC activation program.

M. A. West, R. P. A. Wallin, S. P. Matthews, H. G. Svensson, R. Zaru, H.-G. Ljunggren, A. R. Prescott, C. Watts, Enhanced dendritic cell antigen capture via Toll-like receptor-induced actin remodeling. Science 305, 1153-1157 (2004). [Abstract] [Full Text]

F. Benvenuti, S. Hugues, M. Walmsley, S. Ruf, L. Fetler, M. Popoff, V. L. J. Tybulewicz, S. Amigorena, Requirement of Rac1 and Rac2 expression by mature dendritic cells for T cell priming. Science 305, 1150-1153. [Abstract] [Full Text]